WHEN the FARC guerrillas kidnapped an army general last month, peace negotiations with the government that began two years ago seemed in jeopardy. Colombia’s president, Juan Manuel Santos, responded by calling the FARC’s bluff: he suspended the talks until the general’s release, which came two weeks later.

Now it is the FARC’s turn to raise the stakes. On December 17th it declared a unilateral and indefinite ceasefire. That in its way is historic. Previous ceasefires have only been for short periods. In an announcement in Havana, where the peace talks are being held, the guerrillas said the ceasefire would start on December 20th. They asked several international bodies, including the International Committee of the Red Cross, to verify their compliance.

Many Colombians, weary of a conflict that has lasted half a century, cheered the announcement. But it is not quite the magnanimous gesture it may appear. Iván Márquez, the lead FARC negotiator in the talks, said that the ceasefire would be called off if “our guerrilla units have been the target of attack by the armed forces”.

By attaching that condition, the FARC are trying to force the government to suspend hostilities too. That is a demand that Mr Santos has refused time and again. The government argues that a bilateral ceasefire would only give the guerrillas reprieve from constant military operations against them, which they could use to rearm and regroup, as they did during past, failed peace talks.

Although talking while the fighting continues has sometimes strained the negotiations, these are far more serious than their predecessors. The two sides have reached agreements on the first three agenda items: rural development, political participation and drug trafficking. They are now tackling the two most difficult points: justice and reparations to victims; and the demobilisation, disarmament and reintegration into society of former fighters.

When the talks resumed earlier this month, both sides said they were seeking ways to de-escalate the conflict. The FARC has now issued its proposal in that regard.

Mr Santos did not immediately react. The government can hardly reject the FARC’s gesture but it will have to weigh its response carefully. Suspending attacks on guerrilla units would be tantamount to agreeing to the bilateral ceasefire which Mr Santos has vowed not to declare. But the government could restrict the army to a defensive stance.

It was surely by coincidence that the FARC’s gambit came on the same day as the announcement that the United States and Cuba are to restore diplomatic relations. The FARC have never been beholden to Cuba, and their war has followed its own, tortured logic. But the signs are that Colombia’s long conflict is drawing to a close. Times in the Americas are changing.